1. Field of the Invention
The present invention generally relates to liquid valves and, more particularly, to a miniature valve which is applied to a liquid control system and is used for switching the direction of the liquid flow, or communicating and blocking the liquid flow.
2. Discussion of the Related Art
Miniature valves includes multiple types. Based on the valve structure, they can be generally divided into isolated mode and non-isolated mode; while based on the driving structure, it can be divided into direct-acting mode, lever mode and priority mode. A sealed mode of the miniature valve generally refers to annular seal. Conventional isolated mode, lever-structure and annularly sealed valves are disclosed in U.S. Pat. Nos. 6,003,552, 5,205,323 and 5,199,462. A conventional isolated mode, direct-acting and annularly sealed valve is disclosed in U.S. Pat. No. 4,944,487.
However, these valves disclosed in U.S. Pat. Nos. 6,003,552, 5,205,323 and 5,199,462 have following shortcomings. Firstly, the liquid chambers thereof have a rather complicated shape, thus resulting in leftover and large dead areas therein. Secondly, when switched, the movement of the valve films in these valves results in rather violent liquid fluctuations in pipelines. Thirdly, these valves can be driven by solenoid only. The valve disclosed in U.S. Pat. No. 4,944,487 is subjected to such shortcomings as poor capability of enduring liquid pressure, solenoid drive and narrower application scope.